In recent years, a method of producing a multilayer ceramic circuit board by using a photosensitive conductive paste has been widely used. One of such photosensitive conductive pastes is a photosensitive conductive paste which has been reported in Patent Document 1.
The photosensitive conductive paste of Patent Document 1 is a photosensitive conductive paste that contains metallic particles (Ag particles), a resin having an acidic functional group, and a photoreactive organic constituent and that has a structure in which (a) the median particle size of the metallic particles is 1.5 to 5.0 μm, (b) the ratio of the median particle size of the metallic particles to the crystallite diameter of the metallic particles (median particle size/crystallite diameter) is 35 to 90, and (c) the organic constituent content of the metallic particles is 0.10 mass % or less.
Patent Document 1 states that, when this photosensitive conductive paste is used as a conductive paste for forcing internal conductors (conductor layers) in the case where, for example, a multilayer electronic component constituted by the internal conductors stacked together with insulation layers therebetween is produced, it is possible to reduce or prevent the occurrence of delamination between the internal conductors and the insulation layers, an increase in electrical resistance of the conductor layers, a decrease in insulation performance due to gaps or babbles in the insulation layers, and the like and obtain a multilayer electronic component having good characteristics.
However, in the case where the photosensitive conductive paste of Patent Document 1 is used as a conductive paste for forming inner electrodes, the following problems arise. Since the photosensitive conductive paste shrinks more than the constituent material (ceramic material, which will become insulation layers) of a ceramic multilayer body when fired, the occurrence of delamination cannot necessarily be reduced sufficiently. Furthermore, the above-described difference in firing shrinkage causes a structural defect such as electrode disconnection.
One way to reduce the above-described firing shrinkage is to increase the amount of metallic particles (Ag particles) in the photosensitive conductive paste. However, this has a problem in that increasing the amount or the metallic particles (Ag particles) reduces light transmittance when the applied photosensitive conductive paste is patterned by photolithography and causes a difficulty in precise patterning.
Patent Document 1: Japanese Patent No. 5163687